The present invention relates to a clamp for connecting elongated parts such as rods, pins, pipes or the like. The parts may be cylindrical, and may be parallel or have any angular configuration.
Several clamps for connecting and securing elongated parts and the like have been proposed. However, the clamps of the present invention is superior to other designs in part because the clamps of the present invention grip relatively large areas of the parts to be connected. Many other clamps have only small areas or lines of contact. Gripping a larger area derives at least two advantages. First, the clamping force is more effective. Second, the clamping force is better distributed and therefore less likely to mar or damage the clamped parts. Examples of prior art clamps include U.S. Pat. No. 5,551,660 to Leduchowski. This patent discloses a drum stick holder assembly having an adjustable fastener with a coupling to allow for clockwise or counterclockwise adjustment. Another coupling allows for forwards and backwards rotational adjustments. The assembly has one or two cylinders to house drum sticks. This patent fails to disclose or suggest the use of helical springs or coils that are present in the present invention.
U.S. Pat. No. 4,006,874 to McGee discloses a tube clamp device that includes a sleeve like assembly that has two identical semi-cylindrically shaped half sleeve members. The half sleeve members are sized to the tube diameter being clamped. This claim does not include any helical springs or coils and is designed to connect a tube to a fixed support such as a wall.
U.S. Pat. No. 4,170,995 to Levine, et al., discloses a holder for clamping in place a catheter or other hollow tube using a one piece jaw member mounted on a post with a nut threaded onto the post for adjusting the grip of the clamp. This clamp does not contain any helical springs or coils.
U.S. Pat. No. 5,291,646 to French discloses a clamp used to attach objects to a steering wheel or other type device. The clamp preferably is metal bent to the shape of a xe2x80x9cUxe2x80x9d or a xe2x80x9cVxe2x80x9d. The xe2x80x9cUxe2x80x9d or xe2x80x9cVxe2x80x9d operate as jaws. This clamp has only lines or points of contact with its clamped part.
U.S. Pat. No. 5,774,098 to Calmettes discloses a clamping collar which uses a helical spring that provides pressure to the jaws of the clamp. In this patent, the helical spring or coil does not contact the rod onto which the collar is clamped. In this application, the spring is used to spread apart arms of a pair of pliers.
U.S. Pat. No. 5,833,191 to Gennep discloses a connector that includes a pair of jaws having concave facing gripping services. The connector is a holder for various different objects. The holder cooperates with a xe2x80x9cvise-gripxe2x80x9d type gripping device. The position at which a pair of jaws lock relative to one another is adjustable.
U.S. Pat. No. 5,381,989 to Jackson discloses an adjustable clamp using a helical spring that provides pressure on the jaws and lever arms of the clamp. Again, the helical spring used in this patent is not utilized in the same manner as the present invention.
U.S. Pat. No. 5,674,221 discloses an external fixator for the stabilization of a bone fracture using a xe2x80x9cUxe2x80x9d shaped clamp to secure the pin to the stabilization bar. The clamp holds the pin to the rod by forcing together two skewed cylinders. There are no helical springs included in the design of this clamp. This clamp grips with only lines or points of contact with its clamped part.
One of the novel features of the wrap spring clamp of the present invention is its method of gripping the elongated parts, including cylindrical parts. The clamp grips the parts by twisting a helical coil spring around each part. When the helical spring is twisted in the same direction as its coil, the diameter of the spring is reduced, thereby constricting a part placed within its bore.
Regarding the springs, machined springs, square wire springs, or round wire springs may be used. A machined spring or a square wire spring, when it is tightly wound, grips with nearly its entire inner surface area (the circumference of the bore multiplied by the working length of the spring). A round wire spring will grip along a line that follows the helix of the spring. Therefore, a machined or square wire spring will grip over a greater area than will a round wire spring.
In one embodiment of the present invention, the clamp resembles hinges and within each hinge is a helical spring. Either between the hinges and springs, or incorporated within the hinges or springs themselves, may be coupling devices such as toothed washers. The washers, when used, positively lock the angular configuration between the hinge components. A connection and tightening device such as a bolt passes through the clamp and permits a tightening operation to completely secure the connection. A preferable bolt is a single sex bolt that would require no tools to assemble or tighten. Optionally, the bolt may be made tamper resistant. Therefore, if used as a medical device for holding pins in a bone, the wearer would not be able to unfasten the clamp.
The composition of the clamp is not known to be critical and may be made from different materials depending upon the particular use. For example, the is clamp of the present invention may be fabricated of metal such as stainless steel, titanium, or aluminum. Additionally, the clamp of the present invention may be cast from a polymer or composite.
Because the improved clamp of the present invention secures rod-shaped parts, especially cylindrical or rod-shaped parts, in a new and improved manner, its commercial applications are potentially very broad and not limited to medical devices. This clamp could be incorporated into automobiles, aerospace structures and vehicles, sporting goods, agricultural machinery structures, appliances, furniture, and the like. In addition to orthopedic external fracture fixation, additional examples of uses of the clamp of the present invention include scaffolding and trusses, space structures, air frames, plumbing and chemical processing pipes, adjustable furniture such as computer monitor stands, and temporary fencing, to name a few.
Regarding examples of orthopedic functions, the wrap spring clamp of the present invention may be used as an external fixator clamp for rod to rod and rod to pin connections. Optionally, the clamp of the present invention requires no tools to assemble or to tighten. Therefore, a single tightening operation could secure the connection. Also, as mentioned above, the clamp may be made tamper resistant.
In one embodiment of the present invention, a clamp is disclosed for holding rod members. The clamp comprises a first helical coil defining a cavity to receive a first rod member. The clamp further comprises a second helical coil defining a cavity to receive a second rod member. Finally, the clamp also comprises a connection and tightening device for constricting the first and second helical coils around the respective rod members. This embodiment may also be used as a device for securing a bone. In such a case, this embodiment may comprise a first and second stabilization bar, a pin, a pin attachment device, and a clamp. The pin has a first end suitable for insertion into a bone fragment, and a second end suitable for receiving the pin attachment device. The pin attachment device is suitable for receiving the pin and a stabilization bar. The clamp may be a clamp of the previously described embodiment comprising a first and second helical coil defining a cavity to receive the first and second stabilization bar, and a connection and tightening device for constricting the first and second helical coils around the respective stabilization bars.
In another embodiment of the present invention, a clamp for holding rod members may comprise a first and second connector, a first and second helical spring, and a connection and tightening device. The first and second connectors house the first and second helical springs, and the first and second helical springs define a cavity to house a rod member. The connection and tightening device secures and tightens the first and second connectors by causing the helical springs to constrict about the rod member. Also disclosed in the present invention is a device for securing a bone comprising this embodiment. The device comprises an above-described embodiment of the clamp of the present invention, and further includes a first and second stabilization bar, a pin and a pin attachment device. The pin has a first end suitable for insertion into a bone fragment and a second end suitable for securely receiving the pin attachment device. The pin attachment device is suitable for securely receiving the pin and the stabilization bar. As stated above, this device includes the clamp of this embodiment, wherein the first and second connectors house the first and second helical springs, and the first and second helical springs define cavities to house the first and second stabilization bar. The connection and tightening device secures and tightens the first and second connectors by constricting the helical springs about the stabilization bars.
In another embodiment of the present invention, a clamp for holding a rod member is disclosed, wherein the clamp comprises a helical coil that has a first loop, a second loop, and defines a cavity to receive a rod member. The loops may be formed from the ends of the coils or springs. This embodiment further includes a connection and tightening device received by the first and second loop for constricting the helical coil around a rod member. This embodiment is useful for removably attaching a rod to another device such as a stationary device, not necessarily another rod member.
Finally, in another embodiment of the present invention, a clamp for holding a rod member is disclosed, wherein the clamp comprises a hinge connector, a helical spring, and a connection and tightening device. The hinge connector houses a helical spring and the helical spring defines a cavity to house a rod member. The connection and tightening device secures and tightens the connector by causing the helical spring to constrict about the rod member. This embodiment is also useful for removably attaching a rod member to a stationary device, not necessarily another rod member.